How to treat algae in raw water treatment plant reservoirs?

Algae can be expensive to treat and remove from drinking water.  It can even be deadly.  During summer months algae blooms in raw water reservoirs can be a concern.  Treating the lake with alum treatments is one way to reduce the available Phosphorus within the water.  However, dredging is another method that actually removes phosphorus that is attached to the sediment.  Dredging can improve water quality be removing excessive phosphorus and sediment, reducing treatment costs for algae and turbidity.  Dredging can also increase storage capacity and decrease drought conditions.